1. Field of the Invention
This invention relates to improvements in a clamp band used to clamp and fix a cylindrical member formed of an elastic material to a fixed member having a cylindrical surface.
2. Related Background Art
A clamp band formed of band steel or the like is used to clamp and fix a cylindrical boot, a cover, etc. to a fixed member having a circumferential surface such as the transmission shaft of a vehicle. One known band of this type is designed to be clamped around the outer peripheral surface of a cover cylinder. The band's opposite end portions are initially not coupled to each other but are made into a loop-like shape during clamping. Thus, it is necessary that the clamp band be provided, at the respective end portions, with a tool engaging portion to be engaged by a clamp tool during clamping and connecting portions which engage each other when clamping is terminated.
As regards the connecting portions, it is desirable that they can be simply formed and be of great strength. According to the prior art, it has often been the practice to provide the connecting portions by forming a substantially U-shaped cut-out in one of the end portions of a band and forming a connecting aperture in the other end portion. The ends are connected by bending up the band portion surrounded by the cut-out to the edge portion of the connecting aperture. The upwardly bent portion projects obliquely from the band body by a considerable amount. By connecting the edge portion of the connecting aperture to the upwardly bent connecting projection, the end portions can be brought into intimate contact with each other and can be prevented from being separated from each other.
Because the connecting projection is formed simply by bending up a tongue-like portion, its strength is often not sufficient. Also, it is sometimes the case that after being engaged with the edge portion of the connecting aperture, the connecting projection is deformed (further cocked up in the upright direction), and the great amount of radial protrusion thereof from the connecting aperture may cause the danger of contacting or interfering with the operator's band or the surrounding members.
It has also often been the case that the tool engaging portions are formed on the end portions of the band in the same manner as the above-described connecting projection such that a tool may be engaged with the free end of the bent-up tongue-like portion. The tool engaging portions formed in this manner have a great amount of protrusion from the band body which leads to the ease with which the tool is brought into engagement with the tool engaging portions. However, for the reason set forth above, the tool engaging portions have poor strength and therefore may be deformed or damaged by the friction force acting between the band and the boot or the like being clamped (which friction force may become considerably great depending on the position of the tool engaging portions).